Fluorination of unsaturated compounds



United States Patent 3,422,159 FLUORINATION OF UNSATURATED COMPOUNDS Bernard Sukornick, Morristown, and Christian A. Wamser, Berkeley Heights, N.J., assignors to Allied Chemical Corporation, New York, N.Y., a corporation of New York No Drawing. Filed June 23, 1966, Ser. No. 559,725 US. Cl. 260-648 13 Claims Int. Cl. C07e 17/02; C0111 35/00; C07c 17/04 ABSTRACT OF THE DISCLOSURE Complexes of the formula F NO-X; wherein X is B1 ASF5 or SbF are capable of fluorinating a vareity of aliphatic and aromatic compounds containing double bonds. Such fluorination reactions are characterized generally by the absence of significant cleavage or dissociation of the products as occurs in fluorination reactions using strong fluorinating agents.

This invention relates to the use of complexes of the formula F NO-X; wherein X is BF AsF or SbF as fluorinating agents.

The complex F NO-BF (a stable white solid at temperatures below about 80 C.) and its utility in the purification of F NO, or as an intermediate in the preparation of high energy oxidizers, have been disclosed in co-pending, commonly assigned application of James S. MacKenzie and William B. Fox, Ser. No. 214,157, filed July 23, 1962 now U.S.P. 3,323,866. The complexes F NO'AsF (a stable white solid at temperatures below about room temperature) and F NO-SbF (a stable white solid at about room temperature) and similar utility are disclosed in copending, commonly assigned application of Fox et al., Ser. No. 559,743, filed June 23, 1966.

It has now been found that the above three described complexes, hereafter referred to as the F NO-X complexes, possess unusual and unique fluorinating properties in that they have the ability to fiuorinate unsaturated double bonds in a variety of compounds containing the same to obtain useful fluorinated derivatives in unexpectedly high yields and with a minimum of carbon-carbon and carbon-hydrogen bond cleavage, as takes place in many other fluorination reactions. In most cases, symmetrical addition of two fluorine atoms across the double bond results and it is postulated that the reaction mechanism always follows this course; however, in some instances rearrangement takes place to form the unsymmetrically fluorinated derivatives. Other significant characteristics of the novel fluorination procedure are: it is simple and inexpensive to carry out; it may be carried out under low temperature conditions and at atmospheric pressure; and product recoveries are simple and efficient.

It is accordingly a major object of this invention to provide a novel means for fiuorinating unsaturated double bonds in compounds containing the same, to obtain high yields of fluorinated derivatives without substantial accompanying cleavage or dissociation of the products.

It is another object of the invention to provide a means for fluorinating unsaturated double bonds in compounds containing the same'which does not suffer from many of the disadvantages possessed by prior art procedures for fluorination of such materials.

Another object of the invention is to provide a novel means for fluorinating unsaturated double bonds in compounds containing the same to obtain high yields of fluorinated derivatives containing the same number of carbon atoms, which can be efiiciently carried out at low temperatures and at atmospheric pressure.

3,422,159 Patented Jan. 14, 1969 Yet another object of the invention is to provide a novel fluorination procedure, as above described, in which products can be easily and efficiently recovered.

Other objects and advantages will become apparent from the following description.

The fluorination procedure of the invention is carried out by merely contacting a suitable starting material, containing one or more unsaturated double bonds, with one of the F NO-X complexes at a reactive temperature. The FgNO'X complex may be performed and then contacted with the material to be fiuorinated, or it may be formed in situ in the fluorination reaction by bringing into contact F NO, the X component and the unsaturated starting material, in any order, under reactive conditions.

Preparation of preformed F NO-X complexes may be accomplished by condensing F NO and the desired X component, by means of a vacuum manifold, into a reaction vessel which is provided with external cooling means, such as a liquid nitrogen trap. The reaction vessel should be warmed up and then cooled back down several times in order to get maximum conversions. Synthesis of the F NO-BF complex is discussed more in detail in co-pending application of James S. MacKenzie and William B. Fox, Ser. No. 214,157, mentioned supra. A more detailed description for the preparation of the F NO-AsF and F NO-SbF complexes may be found in co-pending application of Fox et al., Ser. No. 559,743 noted supra.

It has been found that best results are obtained when the F NO-X complex is formed in situ and, when such a technique is employed, it is necessary to first mix the F NO and unsaturated starting material and then add the X component; since, if the F NO and X components are brought together before the unsaturated starting material is added, they will combine immediately and provide what amounts to preformed F NO-X complex. The fluorination reaction will readily proceed when at least one of the reactants present is either in gas or liquid phase. Due to the extremely low vapor pressure of SbF at its melting point (7 C.), however, gas phase reactions with this material are most inconvenient and are therefore not feasible.

Although not absolutely necessary, a solvent may be employed to facilitate contact between the reactants. Criteria for such a solvent are that it should, of course, be a reasonably good solvent for the reactants concerned and that it should also be inert to reactants and the products of reaction. Illustrative suitable solvents which may be employed include such materials as HF, AsF TF and BrF The fluorination reaction may be carried out over a wide range of temperatures, even down to about the temperature of liquid nitrogen (196 C.) and up to about 40 C. or above. As pointed out heretofore, one of the advantages of these fiuorinating agents is that effective fluorination can be carried out at low temperatures thus avoiding conditions under which cleavage and dissociation of products is apt to take place. Room temperature is generally suitable and is most convenient. Preferred temperature ranges, however, will depend upon the particular F NO-X complex being employed. In the case of F3NO'ASF5, the preferred temperature range is between about 0 C. and room temperature. Reaction rates with FaNO'BFg at room temperature and above are unduly slow and the preferred operating range for this reagent is between about 50 and 78 C. The preferred operating temperature range with F NO-SbF is from about 78 C. up to about room temperature.

The fluorination reaction may be conveniently and effectively carried out at atmospheric pressure. Subor superatmospheric pressures may be employed, however.

A 1:1 molar ratio of F NO-X complex to unsaturated starting material is required to complete the fluorination for each unsaturated double bond which is involved. Where the F NO-X reagent is formed in situ, the stoichiometric ratio of F NO to the X component to unsaturated starting materials containing a single unsaturated double bond is 1:1:1. An excess of any one of the reactants will not deleteriously affect the reaction. If more than one unsaturated double bond in the same molecule is sought to be fluorinated; additional equivalent amounts of fluorinating agent are required accordingly. Fluorination will normally proceed progressively, i.e., if one double bond in a compound is more reactive than another, it will react first, and so on, successively.

Apparatus suitable for practice of the invention is any conventional apparatus adapted to facilitate handling and contacting of gaseous reactants and includes the conventional vacuum manifold, provided with a standard vacuum pump and valved outlets to reactant and reaction vessels, which may in turn be provided with external cooling means, such as a Dry-Ice or liquid nitrogen trap. More detailed description of particular apparatus suited for use in accordance with the invention is provided in the appended examples.

Reaction times will vary considerably, depending on such factors as the particular F NO-X complex and unsaturated starting material employed and the reaction temperature; but usually can be controlled by regulating conditions so as to effect reaction virtually instantaneously.

A wide variety of compounds containing one or more unsaturated double bonds may be fluorinated with the F NO-X complexes. Such compounds may be of an aliphatic, cycloaliphatic or aromatic nature or have mixed aliphatic and aromatic moieties. The starting materials may be monoor polyunsaturated double bond compounds and the double bonds may be associated in conjugated form in aliphatic or in aromatic structures or the double bonds may be non-conjugated. The starting materials may also have a variety of functional groups which are unreactive to the F NO-X fiuorinating agents. Illustrative of such functional groups are the following: halogen, N COOH, S0 80 1-1 and P04. Other nonreactive functional groups will readily occur to those skilled in the art and still others may be ascertained by routine testing. Preferred classes of unsaturated starting materials include unsubstituted olefins, such as ethylene, isopropylene and n-hexylene; halogenated olefins, such as tetrafluoroethylene, chlorotrifluoroethylene' and trifluoroethylene; vinyl and allyl compounds, such as vinyl chloride and allyl chloride; cycloaliphatic monoor polyolefins, such as perfiuorocyclohexene and perfluorocyclohexa-1,4-diene; and polyhalogenated aromatic compounds containing at least four chlorine and/or fluorine atoms, such as hexafluorobenzene.

The X components of the novel fiuorinating agents, i.e., BF AsF and SbF are all commercially available. BF has a melting point of about -127 C., a boiling point of about 1 C. at atmospheric pressure and is a colorless gas at standard conditions. AsF has a melting point of about -79.8 C., a boiling point of about -53.2 C. and is also a colorless gas at standard conditions. SbF has a melting point of about 7 C., a boiling point of about 149.5 C. at atmospheric pressure and is a colorless, somewhat viscous liquid at standard conditions.

F NO (trifluoramine oxide) has a melting point of about 161 C., a boiling point of about 89 C. at atmospheric pressure and is a colorless gas at standard conditions. It may be prepared by reacting 0P and NF at temperatures in the range of about 160 to 196 C. and at pressures in the range of about 0-150 mm. of Hg, while under the influence of an electrical discharge. A more detailed description of the preparation of this compound may be found in the co-pending application of 4 James S. MacKenzie and William B. Fox, Ser. No. 214,157, mentioned supra.

The following illustrate practice of the invention with preformed F NO-X complexes without the use of an added solvent:

Examples l-6 Quantities of F NO-BF and F NO-AsF complexes were preformed in glass bulbs of 30120 cc. volume. These reaction vessels were connected to a standard vacuum manifold, evacuated and cooled to liquid nitrogen temperature (196 C.). Equimolar quantities of F NO and BF were condensed successively into some of the bulbs, using standard vacuum line procedures. Other bulbs were charged with equimolar quantities of F N0 and AsF The bulb contents were warmed to 78 C. to form the F NO-BF complex, or to 40 C. to form the F NO-AsF complex. The product mixtures were maintained at the indicated temperatures for about 15 minutes, were recooled to '196 C. and reheated and recooled several times to obtain maximum conversions to the respective complexes. The F NO-BF and complexes were white solids at 78 C. and 40 C., respectively.

Preformed F NO-SbF complex was prepared by a similar procedure except that liquid SbF was introduced into a Monel bulb, the bulb was cooled to 196 C. and evacuated. Slightly more than one equivalent of F NO was condensed into the bulb which was then sealed and warmed to room temperature. The temperature was maintained at this level until the pressure inside the bulb corresponded to less than 10% of the original F NO charged, thus indicating that the reaction was substantially complete.

Next, equivalent weights of selected unsaturated reactants were condensed into the vessels containing the preformed complexes at a temperature of 196 C. The resulting mixtures were allowed to warm up slowly (about 20 hours) to room temperature and the compositions of the resulting product mixtures were determined by infrared analyses. The results of the reactions run in this manner are indicated below in Table I.

CFgCl (10%).

The following illustrate practice of the invention with preformed F NO-X complexes employing an added solvent:

Examples 7-11 Solvents employed were AsF and liquid anhydrous HF. Reaction vessels were of polychlorotrifluoroethylene. Solutions of F NO'X complexes in anhydrous HP or AsF were prepared by condensing equimolar quantities of F NO and the X components into the reaction vessels via all-metal vacuum manifolds, at l96 C. The mixtures were then alternately warmed and cooled as described in Examples 1-6. Anhydrous HF or AsF were then condensed onto the complexes at -196 C. in amounts sufficient to make homogeneous solutions and, in the case of HF solutions of F NO-BF the mixtures were warmed to 78 C.; in the case of AsF solutions of F NO-AsF or of F NO-SbF the mixtures were warmed to C. When the mixtures became homogeneous solutions, they were cooled to -196 C. and equivalent weights of selected unsaturated reactants were condensed into the reaction vessels. The reaction vessels were then sealed and the reaction mixtures warmed slowly the number of moles of unsaturated reactants admitted was equal to the number of moles of F NO reactant already present. Either AsF 0r BF reactant was then introduced into the manifold at a pressure previously determined by calibration, so that when the reaction ves- (over a period of about 1l /2 hours) to 78 C., in sel was opened to the manifold, the AsF or BF comthe case of HF solutions of F NO-BF or to 0 C. in ponent was introduced to the pressure increment which the case of AsF solutions of F NO-AsF or of indicated that equimolar amounts of these materials were F NO'SbF introduced to the systems. The compositions of the prod- 3 5 uct mixtures were determined by infrared and NMR anal- Compositions of the resulting product mixtures were then yses. The results of the reactions run in this manner are determined by NMR and infrared analyses. The results indicated below in Table III.

TABLE III Example X Unsaturated Time Product(s) and Yields Component Reaetant (hrs.) Obtained 12 ASF5 CFz=CF2 I" CzFa (67%).

CF5ONF2 (30%). 13 AsF5 CFz=CFCl 01F501 (90%).

CFZCICFflONFI (5%). 14 ASFIS CFz=CFBr I CzFsBr (90%).

CFzBrCFzONFz (1%). 15 AsF5 CFFCFH I C2F5H (93%). 16 ASFs l. CH2=CH2 I CH3CHF2 (80%).

F F F F 0-0 C=C 17 AsFs FC /CF I F /CF; (70%).

0:0 0:0 F F F F F F C=C\ arc- 3: 18 ASF5 F20 CFz I FzC CF: (100%).

0:0 (1:0 F F F F 19 BF: CF2=CFz 170 CzFa CF3CFzONFz (18%). 20 BFa CH2=CH2 65 CHaCHF2 I*=Essentially immediate formation of the product.

of the reactions run in this manner are indicated below in Table II.

SbF component was not employed in the operational technique employed for Examples 12-20 due to its low vapor pressure and consequent non-feasibility of han- TABLE II dling this material in vapor phase. Exam le FsNO Unsaturated Solvent Pr0duct(s) and P Reactant Remnant Yields Obtained As will be seen from Examples 19 and 20, use of BF;.; component in the indicated procedure at room tempera- 7 F NO-ASF5 CF2=CF2,.. ASF3 C2Ffl (90 7). 8-" FZNOASFL CFFCFCL ASFLW 0217501 (916%) ture resulted in very low reaction rates. As further w ll 9 FSNOBFLM CFFCFL" m, 9 be seen from following Examples 21 and 22, reported in CzFsONFz (40 10 FENOSbFL" CFFCFL ASFzu" 02F 70%) 0 following Table IV, reaction rates with BF component 11 CHFCH," 0113C were substantially increased by operating at lower temperatures.

TABLE IV Example X Unsaturated Temp. Time Product(s) and Component Reaetant Yields Obtained 21 BFQ CF2=CF2 C 50 CiFfl (24%).

CzF5ONF2 (74%). 22 BFZ CF2=CFH 7s 0...- 50 OZF5H (95%).

The following illustrate practice of the invention when fiuorination is carried out with the F NO-X complexes being formed in situ by successively introducing F NO, the X component and the unsaturated reactant into reaction vessels:

Examples 12-20 F NO was introduced, at room temperature, into reaction vessels provided with vacuum stopcocks and connected to standard vacuum manifolds with conventional taper joints. The reaction vessels were glass or metal bulbs and were calibrated so that, after evacuation, gases could be introduced successively at known pressure increments in order that the molar quantities of gases introduced could be ascertained. The bulbs were then sealed and selected unsaturated starting materials were introduced into the vacuum manifold at such a pressure that when the reaction vessels were opened to the manifolds,

wherein X is AsF or SbF with a member selected from the group consisting of unsubstituted olefins, olefins substituted with one or more functional groups which are unreactive to the F NO-X complex, aromatically unsaturated carbocyclic compounds containing a combination of chlorine and fluorine atoms totaling at least four, and 'aromatically unsaturated carbocyclic compounds containing a combination of chlorine and fluorine atoms totaling at least four and additionally substituted with functional groups which are unreactive to the FgNOX comlex.

p 2. The method according to claim 1 in Which the fiuorination is carried out by preforming the F NO-X complex and reacting the preformed complex with the double bond containing compound.

3. The method according to claim 1 in which the fluorination is carried out by preforming the F NO-X complex and reacting the preformed complex and the double bond containing compound in the presence of an inert solvent. I

4. The method according to claim 1 in which the fluorination is carried out by reacting a mixture containing the double bond containing compound, F NO and a member selected from the group consisting of SbF and ASF5.

5. The method according to claim 1 in which the fluorination is carried out by first combining the double bond containing compound with F NO and then reacting this mixture with a member selected from the group consisting of SbF and AsF 6. The method according to claim 5 in which the mixture of the unsaturated compound and F NO is reacted ASF5.

7. The method according to claim 6 which is carried out at about room temperature.

8. The method of claim 1 in which the functional groups which may be substituted on the olefins or aromatically unsaturated carbocyclic compounds may be a member selected from the group consisting of halogen, N0 COOH, S0 SO H and P0 or mirtures thereof.

13. The method for fluorinating double bonds in compounds containing the same which comprises combining a double bond containing compound selected from the group consisting of a non-substituted olefin and a halogenated olefin with F NO at about room temperature, followed by reacting the F NO/dowble bond containing compound mixture with AsF at about room temperature.

References Cited UNITED STATES PATENTS 3,346,652 10/1967 Pilipovich 260 -653 3,062,902 11/1962 Anello et a1 260-6533 DANIEL D. HORWITZ, Primary Examiner.

US. Cl. XJR. 

